IX International Mammalogical Congress, 1 August 2005, Sapporo Convention Center

An adaptive management for sika deer based on sex-specific hunting

H. MATSUDA1, K. KAJI2, H. UNO3, K. Tamada2, T. Fujimoto2, H. HIRAKAWA4, T. SAITOH5, T. Fujimoto6

1Department of Environmental Management, Yokohama National University, Yokohama 239-8501, Japan; 2Nature Conservation Department, Hokkaido Institute of Environmental Sciences, Sapporo 060-0819, Japan; 3 Eastern Hakkaido Wildlife Research Station, Nature Conservation Department, Hokkaido Institute of Environmental Sciences, Kushiro 085-8588, Japan; 4 Hokkaido Research Center, Forestry and Forest Products Research Institute, Hitsujigaoka-7, Toyohira, Saporro 062-8516, Japan; 5 Present address: Kansai Research Center, Forestry and Forest Products Research Institute, Kyoto 612-0855,JapanSapporo 060-0819, Japan; 6 Office of Environmental Affairs, Hokkaido Government, Chuo-ku, Sapporo 060-8558, Japan.

Abstract: We consider a management policy for a sika deer (Cervus nippon) population in the eastern part of Hokkaido. Deer populations are characterized by a large intrinsic rate of population increase and no significant density effects on population growth before population crash. Our goals of management for the deer population are (1) to avoid irruption with a severe damage on agriculture and forestry, (2) to avoid risk of the extinction of the deer population, and (3) to keep a sustainable yield of the deer. To make a robust program based on uncertain information about the deer population, we consider 3 levels of relative population size and 4 levels of hunting pressures. We consider a critical level for the extinction, an optimal level and an irruption level. The hunting pressure for females is set to increase with the population size. We also recommend to catch males if the population size is between the critical and optimal levels and to catch females and males if the population size is larger than the optimal level. We have to avoid cases of irruption or being threatened under various sets of uncertain parameter values. The simulation results suggest that management based on sex-specific hunting is effective to diminish annual variation in hunting yield. We examined an interim assumption of the population size. We first assumed the absolute deer population to be between 74,000 and 166,000 individuals (90% CI) as of March 1994. We took the ratio of the population index obtained by a spotlight census in every year to that in 1993. We estimated the relative population size in 2000 to be between 58 and 101% (95% CI). We analyzed a stage-structured population dynamics model that included uncertainty and yearly changes in parameter values. We assumed that ranges of biological parameter values were consistent with the 16-21% rate of natural population increase per year estimated by a field survey. The population dynamics model suggested that if the population size in 1993 was below 170,000, males would have become extinct. The model also suggested that if its size in 1993 was larger than 330,000, the population would not have subsequently decreased. Therefore, we estimated the population in 1993 to be between these two extremes. We provide a method of reviewing estimates of absolute population size by monitoring subsequent census and harvest data.

[A47] Matsuda H, Uno H, Kaji K, Tamada K, Saitoh T, Hirakawa H (2002) Harvest-based estimation of population size for Sika deer on Hokkaido Island, Japan. Wildlife Society Bulletin 30(4):1160-1171.
[A38] Matsuda H., Kaji, K., Uno, H., Hirakawa, H., Saitoh, T. (1999) A management policy for sika deer based on sex-specific hunting. Researches on Population Ecology41:139-149.